The week will start with a very late season snowfall in the high elevations of the northern Rockies.
A low pressure system is producing widespread rain that will continue to accumulate across much of the region today. According to the National Weather Service (NWS), the intense precipitation rates have driven snow levels down below 7,000 feet, particularly across Lemhi County in eastern Idaho and areas of southwestern Montana. This includes Bannock Pass, Lemhi Pass, US-93 over Lost Trail Pass and Georgetown Lake.
Elevations above 7,500 feet could get hit with snowfall totals of 6 inches through this morning, with as many as 12 inches on some of the tallest peaks. Most spots between 6,500 and 7,500 feet will see around 2 inches of snowfall.
Dan Zumpfe, a NWS meteorologist in Missoula, Montana, told FreightWaves that snowfall down to 7,000 feet or lower in this region in early summer is quite rare.
"Not so rare that it would be unheard of ever in historical records," Zumpfe said. "But it's probably not something you'll see more often than maybe once every 10 to 20 years."
Zumpfe also said truckers may run into minor slushy conditions on paved roads over some mountain passes, but snow won't stick to these roads because the surface temperatures are too warm this time of year. However, some less-traveled and non-paved routes could be more troublesome.
"Anyone who is off the beaten path is going to be faced with snow accumulations that will make travel very difficult and traction very tenuous," Zumpfe added.
He went on to say that the snowfall and low clouds may cause low visibility at times for drivers.
The NWS has issued a Winter Weather Advisory (WWA) for these areas. It is set to expire at noon Mountain Time today as forecasters expect the storm to ease during the afternoon.
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